191 superconductor oxide

Electrodeposition was used to prepare a biaxially textured Gd2Zr207 (GZO) buffer layer on Ni-W substrates.129 Buffer layers provide chemically inert, continuous, and smooth bases for the growth of the superconductor oxide films. They also prevent both the diffusion of metal to the high-temperature superconductor (HTS) layer and the oxidation of the metal substrate when superconductor oxide films are processed at high temperature (-800 °C) in an oxygen atmosphere (100ppm or more). 

Bhattacharya, R. N. Phok, S. Spagnol, P Chaudhuri, T. 2006. Electrodeposited biaxially textured buffer layer for YBa2Cu307 5 (YBCO) superconductor oxide films. J. Electrochem. Soc. 153 C273-C276. 

Another popular titrimetric analysis of superconductor oxidation state is based on the oxidation of ferrous ion (21)-(24) ... 

Surface fluorination in various fluorinated media are currently used nowadays as processes that allow the modifications of many classes of materials, such as metals, intermetallics, semiconductors, carbons, superconductors, oxide ceramics. The above selected examples have illustrated some physical properties that can be drastically modified, including conduction, adhesion, passivation, superconductivity, hy drophobicity / wettability. 

In Figure 4.39, such an superconductor (oxide) is presenting as having the La2CuO or K NiF stmcture, also known as the perovskite of type A B due to the fact that it can not be made by an ABAB... arrangement of perovskite cells. 

The first superconductor oxide at a high critical temperature ( 40 K), was discovered in 1986, and was that one based on the La CuO structure, but with a doped La Sr CuO form, received the Nobel Prize for Physics on 1997 awarded to Geoig J. Bednorz and Alexander K. Muller for their important break-through in the discovery of superconductivity in ceramic materials . ... 

The high-temperature superconductor oxides, in particular YBajOujO (YBCO), have drawn much attention in recent years. YBCO is / -type metal for 6.5 < x < 7. It exhibits superconductivity at reduced temperatures." It is a / -type semiconductor for 6 < x < 6.5, showing a transition to -type conductivity for x Ionic conductivity is difficult to... 

Since scanning tunneling microscopy requires flat conducting surfaces, it is not surprising that most of its early application was to study inorganic materials [17, 19, 20, 29-34]. These studies include investigations of catalytic metal surfaces [24, 35-37], silicon and other oxides [21], superconductors [38], gold... 

Technetium is a silvery-gray metal that tarnishes slowly in moist air. The common oxidation states of technetium are +7, +5, and +4. Under oxidizing conditions technetium (Vll) will exist as the pertechnetate ion, TcOr-. The chemistry of technetium is said to be similar to that of rhenium. Technetium dissolves in nitric acid, aqua regia, and cone, sulfuric acid, but is not soluble in hydrochloric acid of any strength. The element is a remarkable corrosion inhibitor for steel. The metal is an excellent superconductor at IIK and below. 

The superconductor YBa2Cu30g.j, contains copper in both the +2 and +3 oxidation states. Procedures are described for synthesizing the superconductor, demonstrating the superconducting effect, and for determining the amount of Cu + and Cu + in the prepared material. 

C. P. Poole, Jr., T. Datta, and H. A. Farach, Copper Oxide Superconductors, John Wiley Sons, New York, 1988. 

Electrical and Electronic Applications. Silver neodecanoate [62804-19-7] has been used in the preparation of a capacitor-end termination composition (110), lead and stannous neodecanoate have been used in circuit-board fabrication (111), and stannous neodecanoate has been used to form patterned semiconductive tin oxide films (112). The silver salt has also been used in the preparation of ceramic superconductors (113). Neodecanoate salts of barium, copper, yttrium, and europium have been used to prepare superconducting films and patterned thin-fHm superconductors. To prepare these materials, the metal salts are deposited on a substrate, then decomposed by heat to give the thin film (114—116) or by a focused beam (electron, ion, or laser) to give the patterned thin film (117,118). The resulting films exhibit superconductivity above Hquid nitrogen temperatures. 

Oxide superconductors have been known since the 1960s. Compounds such as niobium oxide [12034-57-0] NbO, TiO, SrTi02, and AWO, where A is an alkah or alkaline earth cation, were found to be superconducting at 6 K or below. The highest T observed in oxides before 1986 was 13 Kin the perovskite compound BaPb Bi O, x = 0.27. Then in 1986 possible superconductivity at 35 K in the La—Ba—Cu—O compound was discovered (21). The compound composition was later determined to be La 85 A the Y—Ba—Cu—O system was pubUshed in 1987 and reported a transition... 

Coppet(II) oxide [1317-38-0] CuO, is found in nature as the black triclinic tenorite [1317-92-6] or the cubic or tetrahedral paramelaconite [71276-37 ]. Commercially available copper(II) oxide is generally black and dense although a brown material of low bulk density can be prepared by decomposition of the carbonate or hydroxide at around 300°C, or by the hydrolysis of hot copper salt solutions with sodium hydroxide. The black product of commerce is most often prepared by evaporation of Cu(NH2)4C02 solutions (35) or by precipitation of copper(II) oxide from hot ammonia solutions by addition of sodium hydroxide. An extremely fine (10—20 nm) copper(II) oxide has been prepared for use as a precursor in superconductors (36). 

There are presently four famihes of high-temperature superconductors under investigation for practical magnet appheations. Table 11-25 shows that all HTS are copper oxide ceramics even though the oxygen content may vary. However, this variation generally has little effect on the phvsical properties of importance to superconductivity. 

As an example of the production of oxide systems, the ceramic superconductor YBa2Cu307 j has been prepared tlrrough the reaction... 

In the ceramics field many of the new advanced ceramic oxides have a specially prepared mixture of cations which determines the crystal structure, through the relative sizes of the cations and oxygen ions, and the physical properties through the choice of cations and tlreh oxidation states. These include, for example, solid electrolytes and electrodes for sensors and fuel cells, fenites and garnets for magnetic systems, zirconates and titanates for piezoelectric materials, as well as ceramic superconductors and a number of other substances... 

A unique application of the solid oxygen electrolytes is in dre preparation of mixed oxides from metal vapour deposits. For example, the ceramic superconductors described below, have been prepared from mixtures of the metal vapours in the appropriate proporhons which are deposited on the surface of a solid electrolyte. Oxygen is pumped tluough the electrolyte by the application of a polarizing potential across the electrolyte to provide the oxidant for the metallic layer which is formed. 

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